Summary: QoS Routing for Anycast Communications:
Motivation and an Architecture for DiffServ
Networks \Lambda
Fang Hao Ellen W. Zegura Mostafa H. Ammar
Bell Laboratories Networking and Telecommunications Group
Holmdel, NJ 07733 College of Computing, Georgia Tech, Atlanta, GA 30332
fangh@research.bell­labs.com fewz,ammarg@cc.gatech.edu
Abstract---
Much research in QoS routing has focused on the unicast communication
paradigm. However,another communicationparadigm --- anycasting --- has
grown in importance in recent years. In the anycast paradigm, one endpoint
is specified and the other is selected from a set of ``equivalent'' endpoints.
An anycast service in a QoS­based network requires selection of both an
endpoint and a path that satisfies a QoS constraint. This paper provides
background material on anycasting in both best­effort networks and QoS­
based networks. We then focus on the differentiated services QoS model,
and present the design of a QoS­based anycasting architecture consistent
with that model. Via simulations, we explore the design options implied by
the architecture, including signalling protocols, server selection/sorting al­
gorithms and resource reservation granularity. We conclude by highlighting